Reversible temperature indicators
The reversible strip is composed of a number of printed temperature events that contain different formulations of Liquid Crystal molecules.
Normally, when a solid is heated, at a fixed temperature (termed the melting point) the solid converts straight to an isotropic liquid. However liquid crystalline substances do not convert directly to a liquid but exist as a third state of matter that exhibits the flow properties of a liquid and the optical properties of a solid, before finally converting to a liquid at a higher temperature. These substances are termed Liquid Crystals.
Liquid crystal molecules are very sensitive to temperature and change position, or twist, in relation to changes in temperature. This change in molecular structure affects the wavelengths of light that are absorbed or reflected by the liquid crystals, resulting in an apparent change in the colour of each temperature event. For example, as the temperature increases, the liquid crystal molecules twist slightly in one direction. This twist causes the liquid crystal substance to absorb more of the red and blue portions of the visible light, and reflect the green part. This causes the temperature event to appear green. When the temperature decreases, the molecules begin to twist in the other direction, and reflect a different portion of the spectrum.
LCR Hallcrest are one of the world’s leading manufacturers of Liquid Crystal thermometry products and are dedicated to supplying Liquid Crystal Thermometers, Sheets and Raw Materials for countless markets.
Industrial
Our range of industrial products are suitable for many areas including engineering, electronic, laboratory etc., and can be adapted for many applications.
Medical
From our CE Marked Forehead Thermometer to Drug Testing indicators, these Liquid Crystal strips provide an easy and accurate temperature measuring device.
Safety
Health and Safety is at the forefront of everyday life therefore our thermometers can be utilised as warning indicators for fridges, either at home or in the supermarket through to warning of potentially dangerous hot surfaces.
Education
Our Liquid Crystal Sheets are fascinating for school children and we have been involved with schools and universities around the World who have utilized our technology for various projects. | 
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